EEE: Mosquito numbers are down, but the risk is still there

Tuesday

Nov 5, 2019 at 3:42 PMNov 5, 2019 at 8:04 PM

A hard freeze was recorded locally, which means the mosquito numbers are way down. But, the risk of contracting EEE is still there.

Despite colder temperatures, the risk of contracting the potentially deadly Eastern equine encephalitis virus from a mosquito bite still exists - but it’s low, according to the East Middlesex Mosquito Control Project.

Mosquito numbers have fallen dramatically, according to EMMCP entomologist Doug Bidlack, who said he can't completely rule out the risk.

“As long as there are mosquitoes, I never want to say there is no risk, but the risk is very small,” Bidlack said. “I have never heard of a person getting West Nile virus or EEE this late in our area, but I don’t want to say it can’t happen.”

In an email to the Daily News, state Department of Public Health entomologist Dr. Catherine Brown said determining the end of the mosquito season is complicated, because not all areas have had a hard frost at the same time. Brown added mosquito populations are generally low, even in areas that haven’t had a hard frost.

Kevin Cadima, a meteorologist at the National Weather Service in Norton, said a hard freeze is “more significant (than a hard frost ) when it comes to killing stuff off.” A hard freeze is below 30 degrees Fahrenheit, Cadima said, adding that a hard frost can occur when temperatures are as high as 34. Hanscom Field in Bedford recorded overnight low temperatures on Saturday through Monday of 29, 29 and 28 degrees, respectively.

Those temperatures should mean most MetroWest communities have experienced a hard freeze, Cadima said.

Some adult mosquitoes live through the winter, Bidlack said, especially in places where it’s warmer, with moisture. Locations can include catch basins, basements, garages and barns.

MORE INFORMATION: Read more about mosquito illnesses in 2019

Bidlack stressed it’s unlikely those mosquitoes are transmitting EEE. However, there is a possibility they can transmit West Nile virus.

DPH reported 12 human cases of EEE during this year's outbreak, including three deaths. It reported three human cases of West Nile virus.

Henry Schwan is the health reporter for the MetroWest Daily News. Follow Henry on Twitter @henrymetrowest. He can be reached at hschwan@wickedlocal.com or 508-626-3964.